1. Field of the Invention
The present invention relates to a paper feeding mechanism for a printer and, in particular, to a paper feeding mechanism for a printer capable of appropriately feeding a paper having a large width dimension.
2. Description of the Related Art
As the output apparatuses of computers, word processors, facsimile apparatuses, etc., various printers, such as thermal transfer printers, page printers or the like are generally used.
And, in these conventional printers, there is provided a paper supplying mechanism for supplying one by one a plurality of recording paper sheets stacked together and accommodated by a paper supplying roller, and there is provided a paper feeding mechanism for conveying the recording paper sheets fed from the paper supplying mechanism to a predetermined recording position. Or, there is provided a paper supplying mechanism for continuously supplying a roll of recording paper by a paper supplying roller, and there is provided a paper feeding mechanism for conveying recording paper fed from the paper supplying mechanism to a predetermined recording position.
In such a conventional paper feeding mechanism, there is provided a paper feeding roller which is rotatable by a paper feeding motor, and there are provided a plurality of press contact rollers which are in press contact with the paper feeding roller. And, the recording paper supplied from the paper supplying mechanism is conveyed while being held by the paper feeding roller and the press contact rollers.
Recently, however, a printer is in demand which is capable of performing recording on a recording paper not smaller than A3. In such a printer it is necessary for the length of the paper feeding roller to be made long in accordance with the width of the recording paper.
As a result, the paper feeding roller is deflected due to the weight of the paper feeding roller itself and the press contact force of the press contact rollers, making it impossible to perform rotation with a fixed rotation axis. When the paper feeding roller is thus deflected, a deviation is generated in the conveyance of the recording paper even when the paper feeding roller is accurately rotated, making it impossible to perform accurate conveyance. Further, since the paper feeding roller is rather long, it is difficult to accurately produce a well-balanced paper feeding roller which does not easily involve runout during the rotation thereof. To prevent deflection of the paper feeding roller and reduce runout thereof, the diameter of the paper feeding roller might be increased. However, when the diameter of the paper feeding roller is increased, the production cost of the paper feeding roller increases. Further, the so-called bottom margin (blank area that does not allow printing) cannot be reduced, resulting in a deterioration in the paper feeding performance.